Doug Chapman, Alabama Extension agent for Commercial Horticulture in North Alabama, says the ramifications of having scab disease in your pecan orchards can’t be understated.
“It’s the difference between having pecans and not having them,” Chapman said.
Even as pecan harvest is under way across Alabama, soon it will be time to plant new pecan trees. Pecan planting is usually done during December and January when the trees are dormant.
However, before commercial growers and homeowners begin putting trees in the ground, they must consider their fungicide spray options to manage scab disease. If they don’t have a management strategy, they shouldn’t expect pecans to start falling in 8 to 10 years.
“Scab is My First Suspect”
“Scab can wipe you out. I’ve seen it to where, even if you were to make a few nuts, if there was a scab problem, they tend not to fill out,” Chapman said. “We get a lot of questions like, okay I’ve got pecans and they’re not filling. Here again, scab is my first suspect and until you can eliminate that, there’s not much point in talking about the rest of it.”
Weather was unpredictable this year for pecan growers. Chapman said it was really wet in the spring, but then it turned off dry. He doesn’t think scab was nearly as bad as it has been in other years. But the dry weather has also affected the nut size. If you didn’t have irrigation, the nuts didn’t size up when they should have.
Scab disease does not usually kill trees, but it can greatly reduce yields. The fungal pathogen that causes scab overwinters in the tree as lesions on stems and old nut shucks that remain in the tree after harvest. When temperatures begin to warm in the spring, the fungus becomes active and starts to produce new spores that are spread by rain and wind.